This application claims priority with respect to British Application No. 0029667.3, filed Dec. 6, 2000.
This invention relates to a water spray nozzle, to a pick box provided with such a nozzle, and to a rotary cutting head provided with a plurality of such pick boxes.
Water spray nozzles are conventionally provided on mining equipment for a variety of well known reasons. One known arrangement is a so-called rear entry nozzle whereby a receiving socket is provided in the pick box, and a nozzle is insertable into, and removable from, the rear of the pick box, (having regard to the direction of rotation of the rotary cutting head to which pick boxes are welded), and with a view to avoiding a screw threaded fastening of the nozzle to the pick box, which is difficult to insert and remove in mine conditions, and is subject to rusting, various xe2x80x9cscrewlessxe2x80x9d systems have been developed. One incorporates a circumferential groove intended to house a compressible split ring of spring steel, which after compression (by riding along inclined or chamfered surfaces) expands to latch the nozzle in place. However, due to the need to ensure that the dimensions of the groove are sufficient to accommodate compression of the steel ring, it is not unknown for the free ends of the steel ring to become displaced from the circumferential groove, with resultant loss of concentricity between the steel ring and the nozzle.
A basic object of the invention is the provision of an improved nozzle, pick box, and rotary cutting head.
According to a first aspect of the invention, there is provided an elongate water spray nozzle for use with mining equipment, comprising a cylindrical body member having a leading end and a trailing end, with a circumferential groove provided in the body member towards the trailing end, the groove housing firstly an inner, resiliently deformable xe2x80x98Oxe2x80x99-ring, and secondly an outer, split spring steel latching ring, the xe2x80x98Oxe2x80x99-ring being resiliently operable on the steel ring to bias the steel ring concentrically with the longitudinal axis of the nozzle.
According to a second aspect of the invention, there is provided a pick box having a socket in which is housed a water spray nozzle in accordance with the first aspect.
According to a third aspect of the invention, there is provided a rotary cutting head provided with a plurality of pick boxes in accordance with the second aspect.
The invention thus provides a nozzle in which the steel ring is always retained in a concentric position with respect to the nozzle as a result of the bias of the xe2x80x98Oxe2x80x99-ring, whilst the xe2x80x98Oxe2x80x99-ring is itself compressible by the steel ring, during fitting and removal of a nozzle to and from its socket, thereby presenting no obstruction to compression of the steel ring and hence no adverse effect on the ability of an operator to latch the nozzle in its socket or to unlatch the nozzle for removal from its socket.
The leading end of the nozzle is frusto-conical.
The leading end of the nozzle has a water discharge aperture.
The body member has a water delivery bore leading to the discharge aperture.
The body member has at least one radial water inlet bone leading to the delivery bore.
The body member is provided with a necked portion over a water inlet zone.
A cylindrical filter gauze is mounted on the necked portion.
A circumferential groove is provided beyond both the forward end and the rearward end of the necked portion, each groove housing a water sealing ring, to confine water to the water inlet zone, so as to ensure that the nozzle is balanced, so that there is no water pressure on the nozzle tending to eject it from its socket. Consequently, the latching effect of the steel split ring need only be such as to ensure mechanical retention of the nozzle within its socket.
A mechanical safety latch is provided to restrain uncontrolled ejection of the nozzle from its socket under the influence of water pressure, in the event of failure of the water ring in forward groove.
Adjacent the trailing end of the nozzle is an extraction groove, for engagement by a screw driver blade etc to urge the nozzle rearwardly resulting in compression of the steel ring and xe2x80x98Oxe2x80x99-ring permitting removal of the nozzle.
According to a fourth aspect of the invention, of independent significance, there is provided a pick box having a socket adapted to receive a water spray nozzle of the so-called rear entry type, comprising a cylindrical body member having a leading end and a trailing end, with a circumferential groove provided in the body member towards the trailing end, the groove housing firstly an inner, resiliently deformable xe2x80x98Oxe2x80x99-ring, and secondly an outer, split spring steel latching ring, the xe2x80x98Oxe2x80x99-ring being resiliently operable on the steel ring to bias the steel ring concentrically with the longitudinal axis of the nozzle, the socket having a forward end through which, in use, a water spray may be emitted, and a rearward end, wherein the rearward end is counterbored and tapped, into which is screwed a replaceable retainer sleeve incorporating a first inclined surface at an outer mouth of the retainer sleeve for gradual compression of the steel ring and its xe2x80x98Oxe2x80x99-ring, until an internal step of the retainer sleeve is reached with an increase in diameter after the step permitting radial expansion of the steel ring, and partial or complete decompression of the xe2x80x98Oxe2x80x99-ring, to latch the nozzle in place, with the step providing second inclined surface along which the steel ring is adapted to ride, during nozzle extraction.
The provision of a retainer sleeve means that not only can a damaged or worn retainer sleeve be replaced without having to unweld the pick box from its rotary cutting head, but existing constructions of pick boxes may be converted to those of the fourth aspect.
The retainer sleeve is of non-ferrous material such as brass, or synthetic plastics material such as nylon, so avoiding rusting of a steel insert screwed into a steel housing.
In one embodiment the retainer sleeve is provided with an external collar adapted to seat on an annular periphery of the box adjacent the nozzle receiving socket, and hence to limit the penetration of the retainer sleeve into the counterbore.
The collar is of hexagon profile so that it may be tightened, or untightened, by a spanner.
In another embodiment, no collar is provided and the insert is a flush fit.
The flush nozzle has a diametrical slot, so that it may be tightened, and untightened, by a screwdriver.